[ServiceLocation] In GSoft.Dynamite.PowerShell replace the non-extensible/non-overridable PowerShellContainer with an AddOnProvidedServiceLocator

[taoneill]

The bad part is this: For now, ISharePointServiceLocator doesn't have the methods:

• BeginWebApplicationLifetimeScope or
• BeginFarmLifetimeScope

Those would be essential if you wanted to use PowerShell cmdlets to manipulate SharePoint objects outside a site collection context (e.g. play with a WebApp property bag, etc.).